Recently, as new techniques relating to cameras are being developed, the color reproductivity is surprisingly increasing in quality. Particularly, a white balance control technique has been developed for reproducing a color temperature signal which varies in response to an illumination received from an object and transforming it into a color peculiar to the object by performing a correction during a video signal processing course. This white balance control technique has caused the color reproductivity process to be greatly improved.
In addition, a counter light correction operation has been known in the prior art for correcting for the fact that an object appears shaded if that object is in the vicinity of a bright background. One type of counter light correction involves changing an iris opening reference voltage so as to alter the opening of an iris. Another type involves controlling the amplifying gain of a video signal processing section.
In the above-described conventional white balance control technique, when a user intends to execute a counter light correction by changing an iris opening reference voltage or by controlling the amplifying gain in the amplifying stage during a processing operation of the separated video signal, the camera judges that the color temperature of the environment is changed and executes an undesired white balance control, thus lowering the quality of the color reproductivity of the camera.
That is, there has been a problem in the prior art in that during counter light correction despite the fact that the color temperature of the input signal is not changed, the camera mistakenly judges a change of a signal from a counter light correction device as being a change in the color temperature and thereby executes the white balance control so that the color reproductivity becomes worse.
Accordingly, in Japanese laid open patent publication Sho-62(1987)-175090(Title of invention: Color video camera), there is disclosed a technique in which an iris condition is detected, and the gain of a white balance circuit is controlled in response to the detected iris condition and thereby the color balance correction is executed.
However, in the case of the aforementioned Japanese laid open patent publication Sho-62-175090, although the color reproductivity is increased to a certain degree by executing the white balance correction in response to the iris condition, a fundamental solution could not be offered.
That is, with this conventional device there has been a problem in that since the white balance correction is executed in response to the iris condition, the white balance correction is continually executed even during counter light correction so that the overall quality of the color reproductivity is reduced.